In Office:

Annorax was a brilliant scientist who was made famous for designing a device that theoretically could erase elements from the space-time continuum, anything from a simple molecule to an entire civilization. However, the weapon was never developed and the device never came out of projections, because Annorax decided to spend more time with his wife instead of work on his calculations. During the 2170s, Annorax was living on a Krenim colony at Kyana Prime with his wife. (VOYepisode: "Year of Hell")

In 2382, the Project Full Circle fleet learned of the Krenim and their changes to history, tracing the 'source' of the original alteration to Annorax's equations. However, his work in this timeline focused instead on the dangers of changing history in the manner that he did in the Year of Hell, with the result that the Krenim of the new timeline have established a variation of the Department of Temporal Investigations known as the Krenim Temporal Defense Agency. However, in contrast to the DTI, the Agency's goal appears to be to use time travel to subtly ensure Krenim supremacy in the present timeline, rather than simply preserve the current history, to the extent that they altered a timeline where their past enemies, the Rilnar and the Zahl, lived on a peaceful near-utopian planet, in favour of a timeline where the two were engaged in a protracted and pointless conflict on the same planet, because the peaceful timeline restricted Krenim expansion. (VOYnovel: A Pocket Full of Lies)

In the year2410, during the Iconian War, a Krenim colony at Kyana Prime which possessed Annorax' work developed a way to "mask" their entire planet during the Vaadwaur threat in the Delta Quadrant by taking it out of the timestream, functioning as some kind of cloaking device, however much more complex. After helping a group of Alpha Quadrant Alliance officers to escape a Herald patrol on the planet's moon, the colony leader, Pross, ended up allying himself with the Alpha Quadrant Alliance to develop Annorax's temporal ship in an attempt to defeat the Iconians. (STOmission: "Time in a Bottle")